BS ISO 4251-2:2017 pdf download – Tyres (ply rating marked series) and rims for agricultural tractors and machines Part 1: Tyre designation and dimensions, and approved rim contours
1 Scope
This document establishes the designation in use and the dimensions of the ply rating marked series of tyres for agricultural tractors and machines.
Tyre load ratings are given in ISO 4251-2.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 4223-1, Definitions of some terms used in the tyre industry — Part 1: Pneumatic tyres
ISO 18805 1) , Tyre classification — Agricultural, forestry and construction machines
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4223-1 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
4 Marking
The marking of the ply rating marked series of tyres consists of the designation of tyre size and load rating, and any additional information. See 4.1 to 4.4.
4.1 Tyre size designation
The present size marking for the identification of tyres consists of the nominal tyre width code and the nominal rim diameter code.
EXAMPLE 1
Tyre 13.6 – 28
Tyre 6.50 – 16
For tyres of radial construction, the letter R replaces the dash.
EXAMPLE 2
Tyre 8.3 R 44
For low section height tyres, the letter L is added to the nominal tyre width code.
EXAMPLE 3
Tyre 9.5L – 15
For low section height tractor steering wheel tyres of diagonal construction, an optional marking may be used in the following manner:
Nominal tyre width code/nominal aspect ratio – nominal rim diameter
EXAMPLE 4
Tyre 9.5/85 – 15
4.2 Load rating
The present marking of load rating comprises the ply rating.
EXAMPLE
Tyre 13.6 – 28 8PR
4.3 Categories of use
4.3.1 Agricultural drive wheels — Tractor tyres
The classification code R, as specified in ISO 18805, may be optionally marked at the tyre sidewall.
4.3.2 Agricultural steering wheels — Tractor tyres
The classification code F, as specified in ISO 18805, may be optionally marked on the tyre sidewall. In addition, the letters “FRONT” or “SL” may be marked after the nominal rim diameter code on the tyre.
4.3.3 Agricultural implement tyres
The classification code I, as specified in ISO 18805, shall be marked on the tyre sidewall, along with an optional marking “IMPLEMENT” or “IMP” or “SL” suffix.
EXAMPLE
4.4 Additional information
Tubeless tyres shall be marked with the word “TUBELESS”.
Additionally, classification code markings including tyre classifications may be used as described in ISO 18805, but they are not part of the type size designation of the tyre.
In the case of a preferred direction of rotation of the tyre, an arrow shall be used to indicate that direction.
4.5 Pictogram for maximum tyre bead seating pressure (optional)
The inscription “XXX kPa MAX” inside the pictogram (Figure 1) indicates the maximum cold inflation pressure that shall not be exceeded for bead seating during tyre mounting. The value of the tyre bead seating pressure is determined by the tyre manufacturer.
Figure 1 shows an example of the pictogram to be marked on both sidewalls of the tyre.
5 Dimensions and tolerances
5.1 Agricultural drive wheels — Tractor tyres
Tyre size designations, measurement rims, design dimensions of new tyres, and maximum tyre dimensions in service are given in
a) Table 1 for tyres of diagonal construction with normal section height;
b) Table 2 for tyres of diagonal construction with low section height;
c) Table 3 for tyres of radial construction for special cultivation work.
5.2 Agricultural steering wheels — Tractor tyres
Tyre size designations, measurement rims, design dimensions of new tyres, and maximum tyre dimensions in service are given in
a) Table 4 for tyres of diagonal construction with normal section height;
b) Table 5 for tyres of diagonal construction with low section height.
5.3 Agricultural implement tyres
Tyre size designations, measurement rims, design dimensions of new tyres and maximum tyre dimensions in service are given in
a) Table 6 for tyres of diagonal construction with normal section height;
b) Table 7 for tyres of diagonal construction with low section height.BS ISO 4251-2 pdf download.